In the related art, a light source device converting excitation light emitted from a solid state light source into visible light by using a phosphor and emitting the visible light at a good efficiency has been proposed. Patent Document 1 discloses a configuration of irradiating a circular plate (phosphor wheel) where the phosphor is formed with excitation light (blue laser light) emitted from a light source to emit a plurality of fluorescent light beams (red light beams, green light beams) and using the plurality of the fluorescent light beams as illumination light.